Backrest



FIG. 1 is a top front perspective view of a backrest showing my new design;

FIG. 2 is a right side elevational view thereof; the left side being a mirror image of the right side;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines are for environmental purposes only and form no part of the claimed invention. 

The ornamental design for a backrest, as shown and described. 